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Genetics Ch. 6 and 7 > Test > Flashcards

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1

2 genes are on different chromosomes
(Ex. Seed color and seed texture genes of a pea plant)

The genes segregate independently of one another
(Law of Independent Assortment)

2

Genes that reside on the same chromosome and this cannot segregate independently

Linked genes or linkage groups

3

Genes that are linked are usually...?

Inherited together
(Ex. Blond hair + Blue eyes)

4

Homologous chromosomes can exchange corresponding segments during...?

Propose 1 of meiosis
(crossing over)

5

Further apart on the same chromosome genes are the most likely they are to separate

Recombination

6

Crossing over results in?

Genetic recombination

7

Progeny resulting from crossing over appear in repeatable proportions

Recombinant Frequency

8

Recombinant frequencies for many pairs of linked genes can be used to create..?
Shows arrangement of genes along the chromosome

Genetic Map

9

To measure distances between genes, scientists use?

Map units

10

One map unit corresponds to?

A recombination frequency of 0.01
Referred to as a centimorgan (cM)

11

Greater the distance between 2 genes on a chromosome

The more places between the genes that the chromosome can break
More likely the 2 genes will cross over during synapsis

12

Recombination frequencies are used to give a?

Picture of the arrangement of genes on a chromosome

13

A chromosome map created in this fashion
Portrayal of the sequence of genes on a chromosome
| | |
| | |

Linkage map

14

In the normal process of meiosis, chromosomes pair at the metaphase plate and..?

Subsequently separate and migrate to opposite poles

15

When non disjunction occurs, the chromosomes do not properly separate. Instead..?

Both members of one homologous chromosome pair migrate to same pole

16

As a result of non disjunction..?

Half the gametes will have an extra chromosome and half will be missing a chromosome

17

Single, unpaired chromosome

Monosomy

18

Having 3 chromosomes

Trisomy

19

Gametes with missing or with extra chromosomes are usually?

Sterile

20

Sometimes chromosome imbalances are?
These almost always lead to..?

Fertile
Genetic defects

21

Most chromosome abnormalities are..?

Lethal and cause spontaneous abortion of the embryo

22

What occurs when hen an egg or sperm with an extra chromosome 21 chromosomes fuses with a normal gamete?

Down Syndrome

23

Down syndrome results in a zygote with?

3 copies of chromosome 21
(Trisomy 21)

24

Down Syndrome individuals bear various abnormalities such as...?

Mental retardation, heart defects, respiratory problems, and deformities in external features

25

Results when there is non disjunction of the sex chromosomes

Turner Syndrome

26

Individuals with Turner Syndrome are...?

Physically and sterile

27

Genetic defects can be caused by...?

Inheritance of an allele (Such as in hemophilia)
Or caused by chromosomal abnormalities

28

Chromosomal abnormalities result when the inherited genome is missing a chromosome or has an extra chromosome or when one or more chromosomes have portions...?

Deleted (Deletion)
Duplicated (Duplication)
Move to another chromosome (Translocation)
Rearranged in reverse orientation on the same chromosome (Inversion)

29

Autosomal Recessive
Inability to properly break down the amino acid phenylalanine
Causes mental retardation

Phenylkentonuria (PKU)

30

Autosomal Recessive
Abnormal hemoglobin
Red blood cells are unable to effectively transport oxygen throughout the body

Sickle-cell anemia